Urgent upgrading question.

After getting a gold membership, can I later get a platinum or diamond one?

 Yes you can. I did it. You can upgrade any time you want.

Thank you!

yep - you lose no money - it all gets added into your new membership!

I'm confident the opposite is not true (you cannot 'downgrade' and expect refunds).  I wonder, can you downgrade at all?  Well of course if you're not able to get a partial refund, you'd not bother downgrading.

Anyway, this discussion and other material suggests to me that the risk free route for those members who find 'free' is simply not enough, is when trying out the site's premium offerings might be to aim for: 

1. a 10-day free trial (of Gold, of course),
2. if that pans out to your satisfaction but you're thinking maybe the budget would permit improving on that, then Platinum for a further 10-days and
3. perhaps throwing caution to the winds, Diamond for the final 10-days (assuming that the once in a lifetime 30-day money back guarantee would nonetheless still apply so long as you started your support 'ticket' for a refund within 30-days of starting the whole process).

Then sit back and decide which is truly for you:  free, gold, platinum or diamond.

Does that sound about right?

sftac

You can downgrade, but you don't get a refund. For example, if you ordered 1 year of diamond ($99), and then downgraded to platinum ($49), you would end up with 2 years of platinum (2x$49 ~ $99). 

So, downgrade if you like - you'll still keep your credit.